Auto merge of #10805 - tylersouthwick:webglcontextevent, r=Ms2ger

implement webglcontextevent

fixes #10742

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components/script/dom/document.rs

@@ -77,6 +77,7 @@ use dom::touchevent::TouchEvent;
 use dom::touchlist::TouchList;
 use dom::treewalker::TreeWalker;
 use dom::uievent::UIEvent;
+use dom::webglcontextevent::WebGLContextEvent;
 use dom::window::{ReflowReason, Window};
 use encoding::EncodingRef;
 use encoding::all::UTF_8;
@@ -2168,6 +2169,8 @@ impl DocumentMethods for Document {
                         &TouchList::new(&self.window, &[]),
                     )
                 )),
+            "webglcontextevent" =>
+                Ok(Root::upcast(WebGLContextEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
             _ =>
                 Err(Error::NotSupported),
         }

components/script/dom/webglcontextevent.rs

@@ -41,6 +41,17 @@ impl WebGLContextEvent {
         }
     }
 
+    pub fn new_uninitialized(global_ref: GlobalRef) -> Root<WebGLContextEvent> {
+        // according to https://www.khronos.org/registry/webgl/specs/1.0/#5.15 this is
+        // additional information or the empty string if no additional information is
+        // available.
+        let status_message = DOMString::new();
+        reflect_dom_object(
+                        box WebGLContextEvent::new_inherited(status_message),
+                        global_ref,
+                        WebGLContextEventBinding::Wrap)
+    }
+
     pub fn new(global: GlobalRef,
                type_: Atom,
                bubbles: EventBubbles,